Eldritch Fireblade

This dire sword does double damage to creatures that dwell in cold places. Dire swords bear magical symbols on the blade that let them deal double damage to one kind of creature; against anything else they act as standard magic weapons.

Besides its special power it may carry +1-4 to hit (+1-3 if enchanted with orichalc); every plus adds to both attack and damage rolls, and a magical weapon counts as superior quality when saving against breakage. Magical arms and armor can be enchanted by alchemists using orichalc or by casters of any profession. A caster needs the materials of a minor magic item and a weapon of the finest quality, then one month plus a further month for each spell-like power or +1 conferred, with a 99% chance of success; the finished piece usually sells for at least twice its materials plus 2,000 G.P. per +1. No mortal can enchant anything beyond +4.